# G3_Ortho

## C Specification

    	#include <nitro/gx/g3_util.h>

    	void G3_Ortho(
    	    fx32        t,
    	    fx32        b,
    	    fx32        l,
    	    fx32        r,
    	    fx32        n,
    	    fx32        f,
    	    MtxFx44*   mtx );

## Description

This function sets the Matrix mode to the Projection mode. This function also sets the Orthogonal Projection matrix as the current matrix. When `mtx` is not NULL, the orthogonal matrix will also be set in `*mtx`. This function uses the Divider. The diagram below shows the matrix that is set.

Note: If you set an orthogonal projection, you must use `G3*_SwapBuffers` to select Z buffering. W buffering will not function properly because the depth value will always be fixed.

## Arguments

`t` | Y coordinate at the top of the near clipping plane
`b` | Y coordinate at the bottom of the near clipping plane
`l` | X coordinate at the left of the near clipping plane
`r` | X coordinate at the right of the near clipping plane
`n` | The distance from the eyepoint to the near clipping plane
`f` | The distance from the eyepoint to the far clipping plane
`mtx` | Pointer to a 4x4 matrix

## Return Values

None.

## See Also

`G3_OrthoW, G3_Frustum, G3_Perspective`

## Revision History

02/09/2004 Added a note
01/19/2004 Initial Version